WO2004036165A1

WO2004036165A1 - Food thermometer

Info

Publication number: WO2004036165A1
Application number: PCT/US2003/012724
Authority: WO
Inventors: Conor P. Mcnamara; Larry S. Witt
Original assignee: Wki Holding Company, Inc.
Priority date: 2002-10-17
Filing date: 2003-04-25
Publication date: 2004-04-29
Also published as: AU2003221780A1

Abstract

A food thermometer (10) comprises a probe (18) for extending into meat or into other food while cooking. A thermometer needle (16) is carried in a housing (14) and attached to the probe (18). A temperature sensitive needle position control such as a bimetallic spring (19) controls the position of the needle (16), each end of which registers against a separate, correlated temperature scale (26, 28) to provide a double data readout at a range of specific temperatures. A stop member (32, 34) is positioned to limit the range of rotation of the needle (16) to a limited elevated temperature range.

Description

FOOD THERMOMETER

BACKGROUND OF THE INVENTION

Food thermometers are particularly used for measuring the temperature of meat while in the oven, to determine when the desired food is done. This particularly facilitates cooking of a meat to a desired degree: rare, medium or well done, and also for determining that poultry is sufficiently well done, and that there is no risk of e. coli infection.

" The cooked condition of meat: rare, medium, or well done, for example, correlates with the center temperature of the meat. Accordingly, the idea is known to provide a meat thermometer of the rotating needle type, where the needle points in two opposed directions. One direction indicates the temperature, and the other direction indicates the condition of typical meat dishes at such temperature.

However, as a difficulty with such a system, when such a thermometer is at room temperature, the rotating needle may have rotated so far that its end which normally points at the temperature scale has rotated far enough to point at the other scale carried by such a thermometer, which may indicate the condition of the meat at given temperatures. This raises a particular problem. If such a thermometer needle points at the indicator on such a scale that confirms proper cooking of a poultry dish, when in fact the dish has not been adequately cooked at all, and if a consumer gets confused and believes that the cooking is done, illness can strike, since e. coli or other bacteria present in the poultry may not have been heated enough to be killed. Also, users of the thermometer may be dissatisfied in this circumstance, since they will interpret this as a failure of the thermometer to properly indicate the cooked condition of food.

In accordance with this invention, an improvement is provided to avoid the disadvantages. DESCRIPTION OF THE INVENTION By this invention, a food thermometer, typically for meat, is provided which comprises a probe for extending into meat or other food while cooking. A thermometer needle housing is attached to the probe, and a rotatable thermometer needle having a center pivot is positioned within the housing. A temperature sensitive needle position control, which may be a standard bimetallic control or a Bourdon tube for such type of rotatable needle thermometer, is also provided so that the thermometer needle rotates to indicate the temperature encountered by the probe.

A backing for the thermometer needle is provided, which carries two correlated temperature scales, positioned so that opposed ends of the thermometer needle respectively can point to a position on each scale, to provide a double data readout at a range of specific temperatures.

In accordance with this invention, a stop member, which may comprise several components, is positioned to limit the range of rotation of the thermometer needle to a limited, elevated temperature range which is typically substantially higher than room temperature (approximately 25° C). Thus, with such a limited range of rotation, the double ended thermometer needle will not stray unduly far from its appointed temperature scale, where the wrong needle is pointing at the wrong scale to yield misleading, incorrect information. Instead, the double ended needle of the thermometer is preferably kept immobile at all temperatures outside of the temperature range, and particularly at temperatures below the range. The temperature range has a lower limitation is preferably higher than 100°F, beginning, for example, at about 130° F, and in one embodiment ending at about 200° F, so that the rotatable thermometer needle does not rotate and is immobile at all other temperatures encountered except substantially the temperatures of the range. In some embodiments, the total range of needle rotation is about 140 to 240 angular degrees.

A large variety of designs for the stop member are available, as understood by those skilled in the mechanical arts, for use in the purposes of this invention.

DESCRIPTION OF DRAWINGS

In the drawings, Fig. 1 is a plan view of the face of a meat thermometer in accordance with this invention.

Fig. 2 is an exploded, perspective view of the meat thermometer of Fig. 1.

Fig. 3 is an enlarged, fragmentary perspective view of Fig. 2.

Figs. 4-9 are plan views of the face of the thermometer similar to that of the previous drawings, showing the thermometer temperature indicator needle in different positions. DESCRIPTION OF SPECIFIC EMBODIMENTS

Referring to the drawings, Figs. 1-3 show one embodiment of a meat thermometer 10 in accordance with this invention. Thermometer 10 comprises a needle housing 12, 14 which collectively encloses rotatable thermometer needle 16. Probe 18 is carried by needle housing portion 12, which probe contains a bimetallic spring temperature sensor member 19 of conventional type for use with meat thermometers, connected to rotating temperature indicating needle 16.

As in Fig. 3, needle 16 is attached to temperature sensor member 19 within probe 18, which rotates needle 16 so that needle 16 occupies different positions at differing elevated temperatures. Figs. 4-9 particularly illustrate this, showing how the needle 16 of the thermometer can move relative to the respective two correlated temperature scales 26a, 28a, which are positioned on backing surface 30a behind needle 16. The specific embodiment of Figs. 4-9 differs from the embodiment of Fig. 1 in that the backing 30a exhibits a range of Fahrenheit temperatures from 140°- 190° in an outer position and a Celsius temperature range of 60°-90° in an inner position, while the reverse is true for the embodiment of Fig. 1. Apart from that, the respective thermometers are substantially unchanged.

In Fig. 4, needle 16a points to a temperature below 140° F by its left end 22a.

In Fig. 5, the needle position at 140° F is shown, in which needle end 22a points at the 140° F mark of first scale 26a, and, correspondingly, needle 24a points at an indicator on the second correlated temperature scale 28a, indicating that rare beef and precooked ham will be ready for serving at this temperature.

In Fig. 6, needle end 22a points at 150° F, while needle end 24a points at a location on the second scale 28a between medium beef and rare beef.

In Fig. 7, needle end 22a points at 160° F, and needle end 24a points at the indicator on second scale 28a stating that medium beef and cured ham are ready.

In Fig. 8, needle end 22a points at 171° F on the first temperature scale 26a, and needle end 24a points at the marker on second scale 28a indicating that well done beef, pork and veal are ready.

In Fig. 9, indicator needle 22a points at 181° F, which indicates that the proper temperature for cooking poultry has been achieved. Needle end 24a points at the poultry indicator on scale 28a.

Similarly, in Fig. 1, the thermometer will provide similar temperature indications on first temperature scale 26, correlated with proper conditions for various types of meats on second scale 28, but expressed primarily in terms of Celsius temperature.^' In accordance with this invention, it is desired to limit the range of rotation of needles 16, 16a to a limited, elevated temperature range. Specifically, the range may, in the embodiments shown, be from about 50° to 95° C or 130° to 200°F, which, in these embodiments, incorporates about a 180° rotational swing of needles 16, 16a. Further rotation is prevented by stop members 32, 34, shown best in Fig. 3.

As shown, stop member 32 comprises a ring with a pair of diametrically opposed, outwardly facing prongs 36, attached to the inner end of temperature probe 18 within housing portion 12, as shown. Stop member 34 is secured in non-rotational manner to double ended needle 16, and carries a second prong member 38, which is positioned to engage either of prongs 36 as temperature needle 16 rotates, thus limiting the range of rotation of needle 16 to about 180°, irrespective of the temperature encountered by thermometer 10. Thus, while the thermometers can rotate to record the range of temperatures through the predetermined range of about 130 to 200° F, at temperatures above or below that range, thermometer needle 16 remains in the position shown in Fig. 1, or a position inverted by 180° from that position. Particularly, thermometer needle 16 in Fig. 1 will not rotate further counterclockwise, to cause needle end 22 to point at the "poultry" position, which might tend to deceive the user into believing that their poultry dish was completely cooked, when such is by no means the case, since poultry should be internally heated to a temperature of about 185° F for safe eating.

Thus, a thermometer for food is provided, particularly for meat, in which internal temperatures in the food may be registered on a first temperature scale, 26, 26a, and the correlation of that temperature with respect to cooked meat or other products may be indicated on second temperature scale 28, 28a. However, particularly on cooling of the thermometer, the needle 16 does not rotationally retract to cause the respective needle ends 22, 22a, 24, 24a to point at the wrong scales, and give false, and possibly dangerous, information, because of the stop member 32, 34 utilized herein.

The above has been offered for illustrative purposes only, and is not intended to limit the scope of the invention of this application, which is as defined in the claims below.

Claims

That Which Is Claimed Is

1. A food thermometer which comprises a probe for extending into meat or another food while cooking, a thermometer needle housing attached to the probe, a rotatable thermometer needle having a center pivot in the housing, a temperature sensitive needle position control, and a backing wall for the thermometer needle which carries two correlated temperature scales positioned so that opposed ends of the thermometer needle respectively can point to a position on each scale, to provide a double data readout at a range of specific temperatures, and a stop member positioned to limit the range of rotation of said thermometer needle to a limited, elevated temperature range.

2. The thermometer of claim 1 in which said limited range of rotation is about 140 to 24.0 angular degrees.

3. The thermometer of claim 2 in which said limited, elevated temperature range is higher than 100°F.

4. The thermometer of claim 3 in which said limited, elevated temperature range is from about 140° to 190°F.

5. The thermometer of claim 4 in which said limited range of rotation is about 140 to 240 angular degrees.

6. The thermometer of claim 1 in which said stop member comprises engaging, rotation-limiting prongs which prevent said thermometer needle from rotating beyond a predetermined rotational range.

7. The thermometer of claim 1 in which said temperature sensitive needle position control comprises a bimetallic spring.

8. A food thermometer which comprises a probe for extending into meat or another food while cooking, a thermometer needle housing attached to the probe, a rotatable thermometer needle having a center pivot in the housing, a temperature sensitive needle position control, and a backing wall for the thermometer needle which carries two correlated temperature scales positioned so that opposed ends of the thermometer needle respectively can point to a position on each scale, to provide a double data readout and a range of specific temperatures; and a stop member positioned to limit the range of rotation of said thermometer needle to a limited, elevated temperature range, the lowest portion of which is higher than 100° F, said stop member comprising engaging, rotation-limiting prongs which prevent said thermometer needle from rotating beyond a predetermined rotational range.

9. The food thermometer of claim 8 in which said temperature sensitive needle position control comprises a bimetallic spring.

10. The thermometer of claim 8 in which said limited range of rotation is about 140 to 240 angular degrees.

11. The thermometer of claim 8 in which said limited, elevated temperature range is from about 140° to 190° F.

12. The thermometer of claim 11 in which said limited range of rotation is about 140 to 240 angular degrees.

13. The thermometer of claim 12 in which said temperature sensitive needle position control comprises a bimetallic spring.